The present invention relates to a tamper proof cap which provides a visual indication when the associated prefilled device has been tampered with.
More particularly, the present invention relates to a tamper proof cap for a prefilled syringe.
Syringes prefilled from a central location have become commonplace in a hospital environment in order to control and monitor drugs or other medications which are administered as injectables, i.e. by way of syringes and needles. This method of drug delivery is known as unit dose dispensing. In addition to reducing errors in medication and dosage, better control of inventory and monitoring of usage of drugs, such as controlled substance drugs, is achieved with unit dose dispensing.
Prefilled syringes do not generally include needles since the required needle size is determined by the person who administers the injection. Thus, a readily removable syringe cap was used to close the syringe and protect its sterility while in transit to the patient.
Unit dose dispensing has proven to be an improvement in reducing drug delivery errors. However, since the prefilled syringes were handled by several individuals prior to injection, the uncertainty remained that the drug or medication in the prefilled syringe had been inadvertantly or purposefully tampered with before it was actually administered to the patient. Without an accurate indication as to whether or not the prefilled syringe has been tampered with, it is impossible to determine if the drug had been adulterated or if a prefilled syringe is suitable for rerouting to another patient.
A prior art attempt to provide a tamper proof prefilled syringe utilized a paper, taped over the syringe cap of the prefilled syringe. The paper was torn off to remove the cap and give a visual indication that the prefilled syringe had been opened or otherwise tampered with. Another prior art approach called for packaging the entire prefilled syringe in a bulky plastic bag which was heat sealed. Neither of these solutions proved satisfactory in that they were cumbersome to use and involved additional components, i.e. the tape or bag.
Briefly stated and according to an embodiment of this invention, the problems with the prior art devices have been overcome by the practice of this invention which includes a liquid-impervious closure or stop member providing a removable friction fit with the exit port of a device, such as a syringe, having a liquid reservoir. The stop member is inaccessibly disposed in a cylindrical sleeve member. A cylindrical ring member is concentrically disposed within the sleeve member and about a portion of the stop member. The ring member is connected to the sleeve member by one or more frangible or breakable connections which provide a mechanical coupling with the sleeve member when the sleeve member is twisted, thereby causing the sleeve member to rotate about the end of the syringe or the like.
When the sleeve member is pulled, in an axial direction, off the device, with a force less than the frictional force connecting the stop member with the exit port of the liquid reservoir, the frangible connection is broken and the sleeve member becomes free, thereby indicating that the device which includes the liquid reservoir has been tampered with. The remaining ring member may include an identification portion for inventory control or, for example, to indicate a type, origin, and/or date of the medication.
A support member may form part of a package base for one or more tamper proof caps. The support member provides a friction fit with the sleeve member and traps the stop member between the support member and the ring member. Such a combination provides for the ready coupling of the syringe to the tamper proof cap and the withdrawal of the tamper proof cap from its packaging. In addition, the syringe with its assembled tamper proof cap is designed to be free standing to aid in storage and distribution.